Occultifur plantarum f.a., sp. nov., a novel cystobasidiomycetous yeast species.

Nine strains representing a single anamorphic novel yeast species in dispersed tropical and subtropical habitats were isolated from sugarcane leaf tissue (DMKU-SE24, DMKU-SE45T, DMKU-SE129 and DMKU-SE134) and corn leaf tissue (DMKU-CE36) in Thailand, phylloplane and rhizoplane of sugarcane in Brazil (IMUFRJ 52018 and IMUFRJ 52019), bromeliad leaf tissue in Brazil (IMUFRJ 51954) and plant leaf in Japan (IPM31-24). These strains showed identical or only 1 nt substitution in the sequences of the D1/D2 region of the LSU rRNA gene and 0-5 nt substitutions in the internal transcribed spacer (ITS) region. Phylogenetic analysis based on the combined sequences of the ITS and the D1/D2 regions showed that the eight of these strains represented a single species in the genus Occultifur that was distinct from related species. Occultifur kilbournensis was the most closely related species, but with 0.9-1.2 % nucleotide substitutions in the D1/D2 region of the LSU rRNA gene, and 2.4-2.6 % nucleotide substitutions in the ITS region. They are therefore considered to represent a novel species of the genus Occultifur although the formation of basidia was not observed. The name Occultifur plantarum f.a., sp. nov. is proposed. The type strain is DMKU-SE45T (=CBS 14554T=TBRC 6561T).